An investigation on Vaccinium arctostaphylos L. as a medicinal plant and its micropropagation

Abstract Vaccinium arctostaphylos L. (Ericaceae family), locally named Qare-Qat is a shurb or woody bush which has been extensively used in Iranian folk medicine as antidiabetic and antihypertensitive agents for many years. Phenolics found in leaves and fruits of the plant are a specific group of secondary metabolites that plays an important role of antioxidant activity. The objective of this project was preparation of protocol for micropropagation of V. arctostaphylos and also comparative study of phenolics, anthocyanins and flavonoids contents in V. arctostaphylos methanolic extracts and evaluation of antioxidant activities. Method: Leaves and fruits of V. arctostaphylos were collected from the high altitude areas of Ardabil (Hoor), Gilan (Masouleh and Asalem) and Mazandaran (Kelardasht) provinces in August 2007 and stored at -80¡ÆC until metabolites analysis. Then extraction was carried out with acidified methanol (pH=2) and the mixture was used for antioxidant activity and phenolics content assays by UV- Vis spectrophotometer. In the present investigation, a protocol for micropropagation of V. arctostaphylos, using terminal and lateral nodes from Kelardasht and Asalem forests was developed. Nodal segments were taken from the collected stems. They were surface sterilized and transferred to different culture media (establishment, shoot proliferation and root induction). The experiments were analyzed in factorial based completely random designs. Each experiment was repeated fifth. Analysis of variance was performed and comparisons of means were conducted using Duncan, s Multiple Range Test (p ¡Â 0.01). The results indicated that fruits of Kelardasht genotype had the highest total phenolics content as gallic acid (42.73 ¡¾ 1.5 mg g-1 DW), anthocyanin content as cyaniding-3- glucoside (1.0¡¾ 0.07 mg g-1) and also antioxidant activity (DPPH assay) of fruits of Kelardasht (IC50: 0.14 ¡¾ 0.07 mg ml-1) were highest in comparison to other genotypes. Leaves of Masouleh genotype had the highest flavonoid content as quercetin (2.9 ¡¾ 0.07 mg g-1 DW). The results showed that the best media for Kelardasht and Asalem explants were Anderson (AN) medium supplemented with 1 mg l-1 zeatin (pH= 4.5) and 4 mg l-1 zeatin (pH= 5.5), respectively. In Kelardasht explants, an average maximum number of shoots was obtained in the AN medium containing 2 mg l-1 zeatin (pH= 5). Whereas, the highest number of shoots was achieved in AN medium supplemented with 0.4 mg l-1 IBA and 2 mg l-1 zeatin (pH= 5.5). The highest percentage of rooting was observed after 6 weeks in ¨ö AN medium containing 0.5 mg l-1 zeatin, and 10 mg l-1 IBA (pH= 5.5). The regenerated plantlets were successfully transferred to pit, cocopit and perlit (1: 2: 2). The percentage of survivors was recorded after 50 days. The survival rate was 100%. Conclusion: It could be concluded that the leaves and fruits of V. arctostaphylos have high amount of phenolics and antioxidant activity. Therefore, this plant can be a potential source of antioxidant compounds for food and pharmaceutical industry. Keywords: V. arctostaphylos (Qare-Qat), Anthocyanins, Antioxidant activity, Micropropagation , Root initiation, Shoot proliferation